public class Solution2 {
    public static void main(String[] args) {
        int[] arr = {0,1,0};
        System.out.println(peakIndexInMountainArray(arr));
    }
    public static int peakIndexInMountainArray(int[] arr) {
        int left = 1;
        int right = arr.length - 2;
        while(left < right) {
            int mid = left + (right - left + 1) / 2;
            if(arr[mid] > arr[mid - 1]) {
                left = mid;
            }else {
                right = mid - 1;
            }
        }
        return right;
    }
}
